segment_objects

Segments the moving objects by the background subtraction, and cleans up the foreground with the connected components, publishing their contours and area.

opencv_apps	1.11 and later (ROS 1), 3.0.0 and later (ROS 2)
ROS	noetic, ROS One, jazzy, kilted, lyrical and later
OpenCV	any version of the distributions
Group	Segmentation, the nodes of which publish the mask or label image, ~/image of the color filters and background_subtraction, ~/label of dnn_semantic_segmentation, and ~/contours (ContourArrayStamped) of the regions of segment_objects and watershed_segmentation

Usage

# ROS 2
ros2 launch opencv_apps segment_objects.launch.xml image:=/camera/image_raw debug_view:=false
# ROS 1
roslaunch opencv_apps segment_objects.launch image:=/camera/image_raw debug_view:=false

Try it with the demo video

Download the input video of the demo above, publish it as image with image_publisher, and run the node on it, in the terminals:

wget https://ros-perception.github.io/opencv_apps/media/clips/pool.mp4
# terminal 1: publish the video as image in a loop
ros2 run image_publisher image_publisher_node pool.mp4 --ros-args -p publish_rate:=10.0 -r image_raw:=image
# terminal 2: run the node with the parameters of the demo
ros2 launch opencv_apps segment_objects.launch.xml image:=image use_camera_info:=false
# terminal 3: view the result
ros2 run rqt_image_view rqt_image_view /segment_objects/image

In ROS 1:

# terminal 1
rosrun image_publisher image_publisher pool.mp4 _publish_rate:=10 __name:=camera
# terminal 2
roslaunch opencv_apps segment_objects.launch image:=camera/image_raw use_camera_info:=false

See Credits of the demo videos for the license of the video.

Subscribed topics

Topic	Type
image	sensor_msgs/msg/Image

Published topics

Topic	Type
~/area	std_msgs/msg/Float64
~/contours	opencv_apps/msg/ContourArrayStamped
~/image	sensor_msgs/msg/Image

Services

Service	Type
~/update_bg_model	std_srvs/srv/Empty

Parameters

See also the common parameters.

Name	Type	Default (range)	Changed at run time	Description
queue_size	int	3	no, restart the node	Specigy queue_size of input image subscribers

Source

src/nodelet/segment_objects_nodelet.cpp, launch/segment_objects.launch.xml